Snatch Blocks

[Hybrid_From_Hell]

No they don't!

:P :P

Your right, and if I had explained meself better wrong too

Your right, it that technically they don't, in reality they often are greater as you often do it to have the winch on the base layer of rope winding - giving more "pull" than when on say the 2nd down coil of wire on the drum, with no snatch block

So, my point is that we often use snatch blocks to give the max pull of the winch, and as such your increasing the forces involved, triple line similarly, and thus I always want a snatch block that will take the loads as often your at the top end of the ratings pull wise

Nige

[BogMonster]

Nigel you should get yourself a decent winch with a bit of oomph then you wouldn't need all these snatch blocks

[western]

The load will be the same no matter whether you are winching with a single line or using four snatch blocks, what changes is the amount of force required to move the load; the more snatch blocks - the less force required.

What are the thoughts about this snatch block off Ebay?

Good kit those are, I have 2 as mentioned above, nearly always pick them first for a double or angled line pull.

[landy andy.]

Is it worth having two?

I got two matching ARB's for crimbo and was wondering what to do with the second.

New to all this winch stuff!

Andy

[white90]

Yes indeed we have used two a few times before now.

[Orange]

I'm with Tony on this one... The Black Rat ones have a nice deep groove so the synthetic rope sits in and stays in better. The one that came with my EP9 has sat in the garage and never been used for anything other than a bit of testing, tree moving and bumper straightening!!

[Hybrid_From_Hell]

2 can be seriously useful

For example to get to the 1st line of rope, and to at the same time angle / redirect line of pull

Nige

[roybatty666]

Speak to my women she is an expert on snatch blocks

[pongo]

Your right, and if I had explained meself better wrong too

Your right, it that technically they don't, in reality they often are greater as you often do it to have the winch on the base layer of rope winding - giving more "pull" than when on say the 2nd down coil of wire on the drum, with no snatch block

So, my point is that we often use snatch blocks to give the max pull of the winch, and as such your increasing the forces involved, triple line similarly, and thus I always want a snatch block that will take the loads as often your at the top end of the ratings pull wise

Nige

Beware chaps, the above is not true, and there is danger if you don't understand this. If using the full load of your winch, lets say 8000lb, the load on the attachment point i.e. where the snatch block is connected to the shackle/strop/whatever, and on the pulley shaft WILL be increased; you have 8000lb being applied from the winch and a similar amount by the load, so if the snatch block is turning the rope through 180 degrees the load on the attachment point will be approx 16000lb . Actual applied load will vary with the angles, plues mechanical losses due to friction etc. Table below for reference;

Angle is the measured angle between the legs of the line as they pass over the block sheave. Factor is the multiplier for the applied line load to calculate the block load.

Angle... Factor

0.......... 2

10........1.99

20........1.97

30........1.93

40....... 1.87

50........1.81

60........1.73

70........1.64

80........1.53

90........1.41

100......1.29

110......1.15

120......1

130......0.84

135......0.76

140......0.68

150......0.52

160......0.35

170......0.17

180......0

In #1 above, the angle is 90 degrees, so the factor is 1.41. So a 10,000 pound load will place 14,100 pounds of force on the block/anchor.

NEVER USE UN-RATED KIT. KNOW WHAT LOAD YOU ARE APPLYING. If not, get good medical insurance!

[JST]

Beware chaps, the above is not true, and there is danger if you don't understand this. If using the full load of your winch, lets say 8000lb, the load on the attachment point i.e. where the snatch block is connected to the shackle/strop/whatever, and on the pulley shaft WILL be increased; you have 8000lb being applied from the winch and a similar amount by the load, so if the snatch block is turning the rope through 180 degrees the load on the attachment point will be approx 16000lb . Actual applied load will vary with the angles, plues mechanical losses due to friction etc. Table below for reference;

Angle is the measured angle between the legs of the line as they pass over the block sheave. Factor is the multiplier for the applied line load to calculate the block load.

Angle... Factor

0.......... 2

10........1.99

20........1.97

30........1.93

40....... 1.87

50........1.81

60........1.73

70........1.64

80........1.53

90........1.41

100......1.29

110......1.15

120......1

130......0.84

135......0.76

140......0.68

150......0.52

160......0.35

170......0.17

180......0

In #1 above, the angle is 90 degrees, so the factor is 1.41. So a 10,000 pound load will place 14,100 pounds of force on the block/anchor.

NEVER USE UN-RATED KIT. KNOW WHAT LOAD YOU ARE APPLYING. If not, get good medical insurance!

your both right

if the winch is pulling 8000lbs and that is whats required to extract the vehicle. then on a straight line pull the anchor point has to take 8000lbs.

If you were to double line the winch and you still only needed 8000lbs to extract the vehicle then the winch rope will have 4000lbs in each rope and the anchor point will still have 8000lbs.

However you have the potential to put twice the maximum winch capacity (8000 x2 ) through the anchor point using a snatch block.

using a snatch block does not automatically increase the anchor point load, the load will be the same as a single line pull and it will equal the amount required to extract the vehicle. all the snatch block enables is for you to use a higher load on the same winch hence why it should be rated to twice the pulling power of your winch plus safety factor.

winches loose approx 1000lb of pull per layer of rope. a typical Husky for example has 8000lb pull and 4 layers of rope when 100ft is spooled on so when working with the top layer on a short pull (ie spooling on top of the 3rd layer) you have approx 4000lb capacity. double lining here helps by more rope being out (therefore less on the drum therefore more power any way) plus the pulley mechanical advantage (or choose an anchor point further away!) this is why double lining is not necessarily half the speed of a single line as would be expected by halving the load unless you were pulling with all the rope off on both the single and double line pulls.

[JST]

The load will be the same no matter whether you are winching with a single line or using four snatch blocks, what changes is the amount of force required to move the load; the more snatch blocks - the less force required.

the load is the same BUT the snatch blocks allow the maximum load of the winch (should that be reached) to increase on the anchor point due to the mechanical advantage they provide. the more snatch blocks you have the easier it is for the winch to apply that load.